we're live in san francisco. cate caugiran, cbs 5. >>> president obama told mourners the time has come to find ways to prevent such violent acts in the future. and, of course, gun control was a big issue in the early 1990s. when congress enacted a 10-year ban on assault weapons. now, that ban expired in 2004. some capitol hill democrats are calling for new gun control legislation and california senator dianne feinstein has a bill in the works. >> it will ban the sale, the transfer, the importation, and the possession not retroactively but prospectively and it will ban the same for big cliff drums or strips of more than 10 bullets. >> as for the weapons used in friday's shootings, they were legally purchased by adam lanza's mother, who was among the victims. >>> for continuing coverage of this story, you can visit our website, cbssf.com. >>> there is developing news in san francisco. a home invasion robbery this morning in the sunset district. police were called to the 1600 block of sloat boulevard at about 3 a.m.